How often do you bleed your brakes?

[Drifty//]

If I'm using stock calipers w/ track pads and high temp fluid, am I good just getting the fluid replaced after 3 events or so?

Or should I be bleeding after each one?

[wwjd15]

If running Castrol or Motul 660, I only bleed out the air when there's any, then do a complete flush after 6-8 track days.

If running Motul 600 or similar level brake fluid, 2 days max.

[Drifty//]

Originally Posted by wwjd15

If running Castrol or Motul 660, I only bleed out the air when there's any

Thanks. So, how often does that typically happen? I know it's dependent on one's driving style, but at least in your case?

I'm trying to decide whether I should go ahead and buy a power bleeder. Or whether I can just flush every 6 track days.

[arter]

Go ahead and get a power bleeder. They are only like $50 at Turner or amazon. Makes it very quick and simple to bleed your own brakes ( very little time once you get the wheels off).

[Porschefile]

Originally Posted by Drifty//

Thanks. So, how often does that typically happen? I know it's dependent on one's driving style, but at least in your case?

I'm trying to decide whether I should go ahead and buy a power bleeder. Or whether I can just flush every 6 track days.

It really depends on the car and other factors. It also matters how hard your car stresses the brake system, which in our E92 M3's is a whole lot. I could go many track days without bleeding in my E36 racecar, but that's partially because it was so light and had such effective ducting that it didn't really overheat fluid even when it was older fluid.

Decent fluid (ATE or similar) is cheap enough and bleeding the system is easy enough to bleed at least before each 2 day event for me.

I never liked the power bleeder, I have one and I still use the old fashioned 2 person method. My brakes felt consistently less hard when I used the power bleeder so I quit using it.

[von_zoom]

Well, let me ask everyone - How many times have your brakes failed due to lack of fluid bleeding or changing? I have run a complete HPDE season, 10, 2 day events with the same fluid. I change fluid when I change pads and/or other brake components. I have yet to have a problem. But, I have not experienced any brake situations either since I changed to better pads and ss brake lines.
vz

[Porschefile]

Originally Posted by von_zoom

Well, let me ask everyone - How many times have your brakes failed due to lack of fluid bleeding or changing? I have run a complete HPDE season, 10, 2 day events with the same fluid. I change fluid when I change pads and/or other brake components. I have yet to have a problem. But, I have not experienced any brake situations either since I changed to better pads and ss brake lines.
vz

That is definitely well beyond the normal bleed interval. The point isn't that they will suddenly "fail" necessarily, but over 20 track days it is likely that you will either have small air bubbles in the lines or the fluid will become saturated with water, both of which dramatically lower the boiling point. I have personally had cars get a softer brake pedal that wants to go to the floor due to boiling fluid, it is not a good feeling. If it works for you, great, but definitely be mindful of the risk and pull into the pits if the pedal starts sinking.

What fluid do you run? Some are not very hydroscopic and can be left alone longer, although I've never heard of 20 days without bleeding/flushing.

EDIT: Based on the couple of replies after me, several E9X M3 track guys get away with your bleed/flush interval. Maybe the racecar crowd I'm used to is overly cautious or stress the brake system more?

[CanAutM3]

I flush the entire system once a year in the spring with OEM fluid.

I do about 15 track days per season. I always have my vacuum bleeder with me at the track just in case, but I have never needed it. I never needed to bleed the brakes, good pedal throughout the season. Never lost brakes either. The tracks I run are good for about 135mph. I run el-cheepo Hawks HP+.

[Gearhead999s]

Usually at the start of our season with Motul 600.Never had an issue with poor pedal due to fluid.I have a Stoptech 380/355 BBK and I am quite careful about a cooloff lap to bring the brake temps down before parking the car.I have a lot of fluid boiling issues with parking with hot brakes over the years.Never had an issue with fluid on my 08 with stock brakes.I run a Pagid RS14/29 setup and I am quite aggressive on my brakes.I usually run 15-20 days per year.

[CanAutM3]

Originally Posted by Gearhead999s

Usually at the start of our season with Motul 600.Never had an issue with poor pedal due to fluid.I have a Stoptech 380/355 BBK and I am quite careful about a cooloff lap to bring the brake temps down before parking the car.I have a lot of fluid boiling issues with parking with hot brakes over the years.Never had an issue with fluid on my 08 with stock brakes.I run a Pagid RS14/29 setup and I am quite aggressive on my brakes.I usually run 15-20 days per year.

This is the key .

[von_zoom]

I run ATE Super Blue Racing fluid, boiling point 280 d C. I run PF pads with stainless steel lines on stock rot. and cal. I tend to brake late and hard, so the brakes are not babbied, but they are not abused either. Cool down after a session is taken very seriously- no brake application after the checker during the cool down lap, including entry into the paddock.
vz

[wwjd15]

Originally Posted by Drifty//

Thanks. So, how often does that typically happen? I know it's dependent on one's driving style, but at least in your case?

I'm trying to decide whether I should go ahead and buy a power bleeder. Or whether I can just flush every 6 track days.

It's a difficult question to answer. Typically I would get air in the calipers after 6 hours track time, but sometimes sooner. That's about 2 track days.
However, you need to feel if there's any air in the system.

[Car54]

Originally Posted by CanAutM3

I flush the entire system once a year in the spring with OEM fluid.

I do about 15 track days per season. I always have my vacuum bleeder with me at the track just in case, but I have never needed it. I never needed to bleed the brakes, good pedal throughout the season. Never lost brakes either. The tracks I run are good for about 135mph. I run el-cheepo Hawks HP+.

Really? On your M3? That's suprising...you must be getting lucky because those pads typically are great to the point where they completely fall off a cliff. They're discouraged by many brake companies....I think even Hawk.

[CanAutM3]

Originally Posted by Car54

Really? On your M3? That's suprising...you must be getting lucky because those pads typically are great to the point where they completely fall off a cliff. They're discouraged by many brake companies....I think even Hawk.

Fifth set, no issues.

[Gearhead999s]

Originally Posted by Car54

Really? On your M3? That's suprising...you must be getting lucky because those pads typically are great to the point where they completely fall off a cliff. They're discouraged by many brake companies....I think even Hawk.

A lot of us around here ran the HP+'s till we all got BBKs with no great issues besides the noise on the street.They worked much better than the stock pads.Stepping up the the Pagid RS19's with the stock brakes was a step up and overall worked OK on the track with being somewhat agressive.

[von_zoom]

I used Hawk H10 Gold on my 525 for years, with absolutely no issues or problems. Found them to be great pads.
But based on some of the comments here, I decided to go with Performance Friction pads on stock cal and rot, and have not had any problems there either. Knock wood I guess.
vz

[Car54]

Originally Posted by CanAutM3

Fifth set, no issues.

Originally Posted by Gearhead999s

A lot of us around here ran the HP+'s till we all got BBKs with no great issues besides the noise on the street.They worked much better than the stock pads.Stepping up the the Pagid RS19's with the stock brakes was a step up and overall worked OK on the track with being somewhat agressive.

That's good to hear. The other BMW forum seems to have trouble with them. If you guys have never faded them, then that's a good endorsement. Several students of mine have had them and I've driven on them in our Chumpcar with no issues.

I've always heard HP+ is the best autox pad but not so predictable for track.

[bigjae1976]

Originally Posted by CanAutM3

This is the key .

Yup...and not running your pads down to back plates. You'll transfer more heat to the fluid since there is less pad material to absorb some of the heat.

I usually go about 2-3 weekends on Motul 600 before I flush. Motul 600 is good until you boil it. After that, you must flush.

[Gearhead999s]

Originally Posted by Car54

That's good to hear. The other BMW forum seems to have trouble with them. If you guys have never faded them, then that's a good endorsement. Several students of mine have had them and I've driven on them in our Chumpcar with no issues.

I've always heard HP+ is the best autox pad but not so predictable for track.

If you push the HP+'s hard they do fade but if you are aware of this you can manage this without any real issue.But then again I grew up lapping 5.0 Mustangs with 10" rotors

[swartzentruber]

I'd say as often as you feel a soft pedal. This question is so variable based on brake fluid, track, braking technique (and obviously car). I haven't run the E9x M3 on the track, but I'd say on average you'd likely be okay doing 3 events before bleeding, assuming those 3 are in one calendar year.

[bigjae1976]

Originally Posted by swartzentruber

I'd say as often as you feel a soft pedal. This question is so variable based on brake fluid, track, braking technique (and obviously car). I haven't run the E9x M3 on the track, but I'd say on average you'd likely be okay doing 3 events before bleeding, assuming those 3 are in one calendar year.

Since I DIY my brake bleeds, I try to do it before it gets to that. Nothing worse than missing time at the track for something you could do at home.

3 days on my current fill of Motul 600. Let's see if I can get a 4th.

[swartzentruber]

Originally Posted by bigjae1976

Since I DIY my brake bleeds, I try to do it before it gets to that. Nothing worse than missing time at the track for something you could do at home.

Yeah, no kidding I guess. That's why I finally added an ST-40 to the R32 this year. Almost no amount of bleeding could keep the soft away, and losing time at Road America (my favorite track) last year was the final straw.